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   1 /*
   2  * File:         arch/blackfin/kernel/process.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  Blackfin architecture-dependent process handling.
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/unistd.h>
  33 #include <linux/user.h>
  34 #include <linux/a.out.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/fs.h>
  37 #include <linux/err.h>
  38
  39 #include <asm/blackfin.h>
  40 #include <asm/fixed_code.h>
  41
  42 #define LED_ON  0
  43 #define LED_OFF 1
  44
  45 asmlinkage void ret_from_fork(void);
  46
  47 /* Points to the SDRAM backup memory for the stack that is currently in
  48  * L1 scratchpad memory.
  49  */
  50 void *current_l1_stack_save;
  51
  52 /* The number of tasks currently using a L1 stack area.  The SRAM is
  53  * allocated/deallocated whenever this changes from/to zero.
  54  */
  55 int nr_l1stack_tasks;
  56
  57 /* Start and length of the area in L1 scratchpad memory which we've allocated
  58  * for process stacks.
  59  */
  60 void *l1_stack_base;
  61 unsigned long l1_stack_len;
  62
  63 /*
  64  * Powermanagement idle function, if any..
  65  */
  66 void (*pm_idle)(void) = NULL;
  67 EXPORT_SYMBOL(pm_idle);
  68
  69 void (*pm_power_off)(void) = NULL;
  70 EXPORT_SYMBOL(pm_power_off);
  71
  72 /*
  73  * We are using a different LED from the one used to indicate timer interrupt.
  74  */
  75 #if defined(CONFIG_BFIN_IDLE_LED)
  76 static inline void leds_switch(int flag)
  77 {
  78         unsigned short tmp = 0;
  79
  80         tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
  81         SSYNC();
  82
  83         if (flag == LED_ON)
  84                 tmp &= ~CONFIG_BFIN_IDLE_LED_PIN;       /* light on */
  85         else
  86                 tmp |= CONFIG_BFIN_IDLE_LED_PIN;        /* light off */
  87
  88         bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
  89         SSYNC();
  90
  91 }
  92 #else
  93 static inline void leds_switch(int flag)
  94 {
  95 }
  96 #endif
  97
  98 /*
  99  * The idle loop on BFIN
 100  */
 101 #ifdef CONFIG_IDLE_L1
 102 void default_idle(void)__attribute__((l1_text));
 103 void cpu_idle(void)__attribute__((l1_text));
 104 #endif
 105
 106 void default_idle(void)
 107 {
 108         while (!need_resched()) {
 109                 leds_switch(LED_OFF);
 110                 local_irq_disable();
 111                 if (likely(!need_resched()))
 112                         idle_with_irq_disabled();
 113                 local_irq_enable();
 114                 leds_switch(LED_ON);
 115         }
 116 }
 117
 118 void (*idle)(void) = default_idle;
 119
 120 /*
 121  * The idle thread. There's no useful work to be
 122  * done, so just try to conserve power and have a
 123  * low exit latency (ie sit in a loop waiting for
 124  * somebody to say that they'd like to reschedule)
 125  */
 126 void cpu_idle(void)
 127 {
 128         /* endless idle loop with no priority at all */
 129         while (1) {
 130                 idle();
 131                 preempt_enable_no_resched();
 132                 schedule();
 133                 preempt_disable();
 134         }
 135 }
 136
 137 /* Fill in the fpu structure for a core dump.  */
 138
 139 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 140 {
 141         return 1;
 142 }
 143
 144 /*
 145  * This gets run with P1 containing the
 146  * function to call, and R1 containing
 147  * the "args".  Note P0 is clobbered on the way here.
 148  */
 149 void kernel_thread_helper(void);
 150 __asm__(".section .text\n"
 151         ".align 4\n"
 152         "_kernel_thread_helper:\n\t"
 153         "\tsp += -12;\n\t"
 154         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 155
 156 /*
 157  * Create a kernel thread.
 158  */
 159 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 160 {
 161         struct pt_regs regs;
 162
 163         memset(&regs, 0, sizeof(regs));
 164
 165         regs.r1 = (unsigned long)arg;
 166         regs.p1 = (unsigned long)fn;
 167         regs.pc = (unsigned long)kernel_thread_helper;
 168         regs.orig_p0 = -1;
 169         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 170            mode.  */
 171         regs.ipend = 0x8002;
 172         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 173         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 174                        NULL);
 175 }
 176
 177 void flush_thread(void)
 178 {
 179 }
 180
 181 asmlinkage int bfin_vfork(struct pt_regs *regs)
 182 {
 183         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 184                        NULL);
 185 }
 186
 187 asmlinkage int bfin_clone(struct pt_regs *regs)
 188 {
 189         unsigned long clone_flags;
 190         unsigned long newsp;
 191
 192         /* syscall2 puts clone_flags in r0 and usp in r1 */
 193         clone_flags = regs->r0;
 194         newsp = regs->r1;
 195         if (!newsp)
 196                 newsp = rdusp();
 197         else
 198                 newsp -= 12;
 199         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 200 }
 201
 202 int
 203 copy_thread(int nr, unsigned long clone_flags,
 204             unsigned long usp, unsigned long topstk,
 205             struct task_struct *p, struct pt_regs *regs)
 206 {
 207         struct pt_regs *childregs;
 208
 209         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 210         *childregs = *regs;
 211         childregs->r0 = 0;
 212
 213         p->thread.usp = usp;
 214         p->thread.ksp = (unsigned long)childregs;
 215         p->thread.pc = (unsigned long)ret_from_fork;
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * sys_execve() executes a new program.
 222  */
 223
 224 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 225 {
 226         int error;
 227         char *filename;
 228         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 229
 230         lock_kernel();
 231         filename = getname(name);
 232         error = PTR_ERR(filename);
 233         if (IS_ERR(filename))
 234                 goto out;
 235         error = do_execve(filename, argv, envp, regs);
 236         putname(filename);
 237  out:
 238         unlock_kernel();
 239         return error;
 240 }
 241
 242 unsigned long get_wchan(struct task_struct *p)
 243 {
 244         unsigned long fp, pc;
 245         unsigned long stack_page;
 246         int count = 0;
 247         if (!p || p == current || p->state == TASK_RUNNING)
 248                 return 0;
 249
 250         stack_page = (unsigned long)p;
 251         fp = p->thread.usp;
 252         do {
 253                 if (fp < stack_page + sizeof(struct thread_info) ||
 254                     fp >= 8184 + stack_page)
 255                         return 0;
 256                 pc = ((unsigned long *)fp)[1];
 257                 if (!in_sched_functions(pc))
 258                         return pc;
 259                 fp = *(unsigned long *)fp;
 260         }
 261         while (count++ < 16);
 262         return 0;
 263 }
 264
 265 void finish_atomic_sections (struct pt_regs *regs)
 266 {
 267         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 268                 return;
 269
 270         switch (regs->pc) {
 271         case ATOMIC_XCHG32 + 2:
 272                 put_user(regs->r1, (int *)regs->p0);
 273                 regs->pc += 2;
 274                 break;
 275
 276         case ATOMIC_CAS32 + 2:
 277         case ATOMIC_CAS32 + 4:
 278                 if (regs->r0 == regs->r1)
 279                         put_user(regs->r2, (int *)regs->p0);
 280                 regs->pc = ATOMIC_CAS32 + 8;
 281                 break;
 282         case ATOMIC_CAS32 + 6:
 283                 put_user(regs->r2, (int *)regs->p0);
 284                 regs->pc += 2;
 285                 break;
 286
 287         case ATOMIC_ADD32 + 2:
 288                 regs->r0 = regs->r1 + regs->r0;
 289                 /* fall through */
 290         case ATOMIC_ADD32 + 4:
 291                 put_user(regs->r0, (int *)regs->p0);
 292                 regs->pc = ATOMIC_ADD32 + 6;
 293                 break;
 294
 295         case ATOMIC_SUB32 + 2:
 296                 regs->r0 = regs->r1 - regs->r0;
 297                 /* fall through */
 298         case ATOMIC_SUB32 + 4:
 299                 put_user(regs->r0, (int *)regs->p0);
 300                 regs->pc = ATOMIC_SUB32 + 6;
 301                 break;
 302
 303         case ATOMIC_IOR32 + 2:
 304                 regs->r0 = regs->r1 | regs->r0;
 305                 /* fall through */
 306         case ATOMIC_IOR32 + 4:
 307                 put_user(regs->r0, (int *)regs->p0);
 308                 regs->pc = ATOMIC_IOR32 + 6;
 309                 break;
 310
 311         case ATOMIC_AND32 + 2:
 312                 regs->r0 = regs->r1 & regs->r0;
 313                 /* fall through */
 314         case ATOMIC_AND32 + 4:
 315                 put_user(regs->r0, (int *)regs->p0);
 316                 regs->pc = ATOMIC_AND32 + 6;
 317                 break;
 318
 319         case ATOMIC_XOR32 + 2:
 320                 regs->r0 = regs->r1 ^ regs->r0;
 321                 /* fall through */
 322         case ATOMIC_XOR32 + 4:
 323                 put_user(regs->r0, (int *)regs->p0);
 324                 regs->pc = ATOMIC_XOR32 + 6;
 325                 break;
 326         }
 327 }
 328
 329 #if defined(CONFIG_ACCESS_CHECK)
 330 int _access_ok(unsigned long addr, unsigned long size)
 331 {
 332         if (size == 0)
 333                 return 1;
 334         if (addr > (addr + size))
 335                 return 0;
 336         if (segment_eq(get_fs(), KERNEL_DS))
 337                 return 1;
 338 #ifdef CONFIG_MTD_UCLINUX
 339         if (addr >= memory_start && (addr + size) <= memory_end)
 340                 return 1;
 341         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 342                 return 1;
 343 #else
 344         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 345                 return 1;
 346 #endif
 347         if (addr >= (unsigned long)__init_begin &&
 348             addr + size <= (unsigned long)__init_end)
 349                 return 1;
 350         if (addr >= L1_SCRATCH_START
 351             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
 352                 return 1;
 353 #if L1_CODE_LENGTH != 0
 354         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
 355             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
 356                 return 1;
 357 #endif
 358 #if L1_DATA_A_LENGTH != 0
 359         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
 360             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
 361                 return 1;
 362 #endif
 363 #if L1_DATA_B_LENGTH != 0
 364         if (addr >= L1_DATA_B_START
 365             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
 366                 return 1;
 367 #endif
 368         return 0;
 369 }
 370 EXPORT_SYMBOL(_access_ok);
 371 #endif /* CONFIG_ACCESS_CHECK */